South African succulents Archives - Page 18 of 47

Cheiridopsis namaquensis (part 1 of 2)

One of the many older names for this plant is Mesembryanthemum cigarettiferum.
Gustav Schwantes in his magnum opus “Flowering stones and Midday-Flowers” (1957) gives a wonderful description of the species, referring to that name as follows:
“…It was a small, tufted, branched plant, on which were a number of cylindrical structures with dry skins like paper bags; from each of them projected the tip of a pair of leaves at rest within. These paper bags were formed by the drying up of earlier leaf pairs which had been joined for a long way up. The young pair of leaves inside them was. however, much more deeply divided. The surrounding bags reminded Berger so strongly of the paper mouthpiece of a cigarette that he gave it the very descriptive name of Mesembryanthemum cigarettiferum, the Mesembryanthemum bearing cigarettes. The leaves at rest within the bags, when the plants had been potted up and started into growth, grew out of the bags and developed into thick, narrow leaves such as are often found in the Mesembryanthemaceae and produced from the centre an equally narrow pair of leaves, which, however, were joined for a considerable distance so that only the extreme ends of the leaves appeared as free tips. Within this pair of leaves, which looks like a cylinder with little horns at the top, the young, but deeply divided, pair develops; it draws on the pair surrounding it so that this finally becomes the protecting skin, the paper bags referred to above. Clearly this is a case of one of the many interesting contrivances for protecting the young growth from the rigors of the dry period. This protection is achieved here in the same way as in Ruschia pygmaea (see picture #2, FN) and many other species of Mesembryanthemaceae.”

The plants form compact clumps with many branches, up to 20 cm in diameter, with
light blue-grey to green-grey leaves.
The flowers appear from July to October and are about 4.5 cm in diameter; they open in the early afternoon.
Widespread on shale slopes and flats at an altitude of 300-950m from Namaqualand to the western Little Karoo and the only Cheiridopsis that occurs this far south.

Pictures taken near Matjiesfontein on the following dates:
#1 31 Jan. 2009
#2 18 Feb. 2007
#3 and #4 17 May 2008

Bulbine mesembryanthoides (part 3 of 3)

Subspecies namaquensis differs from its sibling by having no more than two leaves, one of which is usually inconspicuous.
The inflorescence is shorter (5-10 cm tall) and always single and the filaments have a double tuft of hairs.
These plants occur only in the Northern Cape, from Springbok to the Richtersveld in gravelly places.

Bulbine mesembryanthoides (part 2 of 3)

One often comes across the name of the species as Bulbine mesembryanthemoides, but because Haworth used the spelling mesembryanthoides in his original description, this has to be accepted as correct.

Subspecies mesembryanthoides has a small underground tuber and usually 1-2
leaves (rarely up to 4). The leaves are cylindrical, 1-2.5 cm tall and up to 2 cm in diameter. As soon as the dry summer period arrives, they start to whither.
Flowers appear in spring and summer (Augustus-November), usually after the leaves have retracted. Each plant may have 1-3 inflorescences up to 20 cm tall.
This subspecies occurs widespread from the Knersvlakte in southern Namaqualand to Graaff-Reinet in the Eastern Cape on rocky slopes and flats.

bulbmesemes 1773-Edit

bulbmesemes 20141123-9549

bulbmeseDSC_3941

bulbmesemes 2014 11 23-9551

bulbmesemes 20141123-9539

bulbmeseDSC_3931

Bulbine mesembryanthoides (part 1 of 3)

If there were a list of favourite types of succulents, I’m sure the so-called window plants would rank very high. Most of these plants belong to the Aizoaceae (Mesembs), but they are also found in Bulbine and Haworthia.
When one looks up information on window leaves, one gets the impression they are all built on the same principle: the surface of the leaf tip lacks chlorophyll, the central parenchyma* reaches up to the epidermis and as a result of this combination, the leaf tip looks and acts like a window.
In a few cases however, the windows are formed differently.
It has taken me quite a while to find a place where this is described in a comprehensive as well as comprehensible way.
In Cactus & Succulent Journal (US) vol. 16, 1974, Werner Rauh published an article called Window-leaved succulents. He starts his explanation with a description of Haworthia obtusa (=cooperi) var. pilifera and uses more or less the following wording:
“The numerous fleshy leaves are nearly hidden in the substratum and we can only see the transparent, glass-like leaf tips, ending in a long hair. The transparence of the leaf tips is caused by a lack of chloroplasts**. We find the assimilation parenchyma only in the lower two thirds of the blades, but these leaf parts are not accessible to the light. The consequence of this anatomical structure is that light, necessary for assimilation, can reach the assimilation parenchyma only by passing the transparent windows. But the leaves of H. pilifera are not in the morphological sense true window leaves.”
He then moves on to Haworthia obtusa (=cooperi) var. dielsiana, saying:
” … the most remarkable feature is the behaviour of the leaves in the course of their development: young leaves are of the same shape as those of H. pilifera, but becoming older, the upper third of the lamina, which exceeds the soil surface, dies off, so that only the water parenchyma, covered by the shrunken epidermis is to be seen. The lower parts of the leaves with the assimilation parenchyma are hidden in the ground; sunlight can reach it only by passing through the water parenchyma.”
This is the same type of window formation we find in Bulbine mesembryanthoides. In Rauh’s words:
“Becoming older, the upper parts of the leaves die off, as in Haw. obtusa var. dielsiana and the result is the formation of a big window with a plane surface. The assimilating parenchyma is completely hidden in the substratum.”

We know that strong sunlight destroys the chlorophyll, which is essential for the plant’s metabolism.
Window-leaved plants are hidden in the ground (at least in the hot and dry season) and sunlight can reach the assimilation tissue only through the windows, passing through the water parenchyma. This filtering process protects the plants against very strong light.
In experiments carried out with Fenestraria, it was found that the light is reduced so much that the chloroplasts will not be damaged, but stays strong enough to allow sufficient assimilation and production of organic substance.

* parenchyma is the relatively undifferentiated tissue that makes up the bulk of many plant organs and is often used for storing of water or food.
** chloroplasts are the tiny parts within plant cells that contains chlorophyll.

bulbmesemes 8208#2012-11-01 — This is what the plants look like when the tips of the leaves start dying down.

bulbmesemes Scan161 — At the end of the process the plants look like this.

Gibbaeum velutinum

With their broad, boat-shaped, yellowish-green leaves, these plants rather look like Glottiphyllums, but the cover of short soft hairs will soon tell you differently. The leaf pairs are very unequal, with the longer leaf up to about 5 cm long.
The flowers are 2-2.5 cm in diameter, usually pink-purple with a darker purple mid-stripe, and appear in late spring (mainly October-November).
In the western Little Karoo (from Barrydale to Muiskraal), the plants are often abundant on shallow clay soils in the shade of bushes.
The species is similar to G. schwantesii which is more robust, does not have its stem embedded in the ground and is much rarer (known from only one locality).
The first three pictures were taken in summer (two days ago), the last one in autumn (13 March 2007).

gibbvelu DSC_1819 — Close friends with Haworthia mucronata

Pelargonium luteolum

About 70 species of Pelargonium belong to the section Hoarea: deciduous geophytes with turnip-shaped or elongated tubers. Several of these plants have similar leaves, so one needs flowers to positively identify them.
P. luteolum possesses a large tuberous rootstock and a number of smaller tubers and
leaves 4-7 cm long and 3-12 cm wide which are dry at flowering.
The inflorescence has 2-3 branches and is up to 20-30 cm tall.
Each of the branches bears to 16 flowers, which are about 1.5 cm in diameter and pale yellow, sometimes pink, with dark red-purple lines on the two upper petals. They usually appear from November-March, but sometimes as late as May.
The plants are widespread in various -usually rocky- habitats from southern Namaqualand to Steytlerville and Mossel Bay. This is mainly a winter rainfall area, with about 100-300 mm rain per year. They seem to be especially plentiful in the Worcester-Montagu area.

The three overlapping lower petals -hiding the style and stamens-are characteristic for this species. The literature tells us that they are arranged in such a way that the lateral ones partly overlap the central one. When you look closely at the last picture, you will see that the arrangement is sometimes the other way round: here the central one of the three lower petals lies on top of the two lateral ones.

The first picture was taken 27 June 2010, the next three 22 Jan. 2016 and the last one 21 Febr. 2009.

Marlothistella uniondalensis

Both species in this genus (the other one is M. stenophylla) are characterized by having thick, branched tap-roots.
In this species the leaves are up to 45 mm long and about 5 mm wide.
The showy flowers are often striped and appear in July/August. At least that is what the literature tells us. The photos below however were taken at the end of October.
The plants occur in open patches in grasslands, fynbos or karroo vegetation from Beaufort West to Uniondale, Prince Albert and Oudtshoorn. Again: that is according to the literature, but the pictures were taken rather further west, near the northern entrance to the Seweweekspoort.

Othonna carnosa

Since its publication in 2000, “Cape plants” by J. Manning & P. Goldblattt has been one of my main sources of information on plants of southwestern South Africa. In 2012 a new edition was published, with the somewhat unwieldy title “Plants of the Greater Cape Floristic Region 1: The Core Cape Flora”. At the same time a companion volume appeared covering the flora of Namaqualand-southern Namibia and the western Karoo, called “Plants of the Greater Cape Floristic Region 2: The Extra Cape Flora”, edited by D. A. Snyman.
I acquired this set recently and am enjoying the great amount of new information.
One of the first things I did was looking at slides of plants I have not been able to identify yet and, as expected, this has already produced some ID’s. A peculiar thing I found out is that, where a species is mentioned in both volumes, the info is not always consistent. The subject of this blog is a case in point.
When identifying plants of the genus Othonna, one of the most important questions is whether the flower heads are disciform or radiate.
In the first case, all the little flowers in the flower head look more or less the same; in the second case, the flowers along the margin of the head resemble normal petals.
Pictures are usually easier to understand: the flower heads of the first species below (Othonna euphorbioides) are disciform; the ones of O. carnosa are radiate.

When I went through the text in my new acquisition, to see if I could identify the following pictures, I came across the name Othonna carnosa with the following info:
“Succulent shrublet with short, erect or sprawling branches, 10-30 cm. Leaves fleshy, ovoid to fusiform (egg- to spindle-shaped FN). Flower heads radiate, few in lax, terminal cymes on slender peduncles, yellow or white. Flowering mainly April-October. Sandstone slopes and stony flats. ”
Strangely enough, when I checked the description in Volume 2, some of the information appeared to be different: “Flower heads solitary , disciform , yellow.”
The first two pictures below were taken at the same place, with a few minutes in between. As you can see, in the first picture the flower heads are solitary, and in the second the peduncles are divided.
The disciform/radiate and yellow/white questions still remain to be answered, but I am now convinced that the following pictures show O. carnosa.

Othonna taraxacoides

Almost two years ago I published a post on Othonna auriculifolia. Today’s subject could be considered the northern counterpart of that species. Both were described in the first half of the 19th century, when taxonomy was still a very European science. This probably explains why both specific epithets refer to well known European plants: taraxacoides means looking like a Taraxacum (dandelion) and auriculifolia means with leaves like Primula auricula (bear’s ears or cow slip).

O. taraxacoides is a stemless tuberous geophyte up to 10 cm tall. The leaves are leathery and wedge- to egg-shaped or more or less kidney-shaped. Usually they are 2-3 cm long and up to 2 cm wide, with small rounded teeth and often incised with 3-5 rounded lobes.
The flower heads are 0.8-1.5 cm in diameter and appear in July and August.
The plants occur on open pebbly places or quartz patches from the
Richtersveld to Kamieskroon.

Hoodia (Trichocaulon) alstonii

Of the small-flowered Hoodias this is by far the tallest, with plants growing into many-stemmed shrubs up to slightly over a meter tall and 0.5 m wide.
The stems have an unusual whitish, grey-green colour and their 20-22 obtuse angles are armed with exceptionally hard and sharp spines.
The upper parts of the stems produce large numbers of flowers 1-1.8 cm in diameter.
The species has an unusual distribution. It occurs in the winter rainfall area of
Namibia on stony hillsides east of Luederitz and along the lower reaches of the Orange River.
In South Africa it also occurs along the lower Orange River: the western part of the area here receives rainfall in winter, whereas in the eastern part the rain falls in summer.
These habitats are surprisingly arid and in general the plants grow in the open on either rocky slopes or stony, flat areas.